Small Hepatocellular Carcinoma and Dysplastic Nodules in Cirrhotic Livers: Differentiation with Dynamic MR Imaging

Abstract

Objective: To evaluate the usefulness of spin-echo T2and T1-weighted images and contrast-enhanceddynamic gradient-echo images in differentiatingbetween hepatocellular carcinoma and dysplasticnodules in cirrhotic livers.Method: Thirty-eight patients with liver cirrhosisunderwent spin-echo T2 and T1-weighted andcontrast-enhanced dynamic gradient-echo imaging. 16small hepatocellular carcinomas (< 3 cm) in 16 patientsand 12 dysplastic nodules (> 1 cm) in 12 patients wereincluded in this study. Spin-echo sequences anddynamic examination were compared forcharacterisation of liver lesions.Results: On combined SE T2 and T1-weighted imagesand dynamic MR images, the most commonappearances were hyperintensity on T2-weightedimages (63%), hyperintensity on T1-weighted images(50%) and hypervascularity (88%) for hepatocellularcarcinomas. All of the dysplastic nodules wereisointense on T2-weighted images and except one, alldysplastic nodules enhanced similar to the liverparenchyma.Conclusion: In the differential diagnosis of focal lesionsin cirrhotic liver, contrast enhancement features areas diagnostic as the signal intensity of the lesions onspin-echo sequences. Hyperintensity on T2-weightedimages and hypervascularity on dynamic contrast-enhanced MR imaging are statistically significantfeatures of HCCs developing in cirrhotic livers.Key words: Cirrhosis, MR, liver neoplasms, diagnosis